individuals with certain traits in particular environments are more likely than others to survive and have offspring
whether a characteristic is considered advantageous or disadvantageous depends on the environment (when the environment changes, the advantageous or disadvantageous characteristics can also change)
a population is a group of individuals that belong to the same species, live in the same area, and breed with others in the group
a species is a group of organisms that look alike and are capable of producing fertile offspring in nature
biodiversity is the variety of species living within an ecosystem
mutation, crossing over, and independent assortment are the mechanisms by which genetic variation is created at the molecular level
Translating Standards into Learning Goals (The “Unpacking”):
students should be able to make this key association: individuals that have physical or behavioral traits that better suit their environment are more likely to survive and reproduce than those that do not have such traits
students should be able to explain what is meant by “differential reproductive success” between organisms as the difference between how many offspring individuals are able to leave behind.
students should be able to recognize that an individual with higher reproductive success leaves behind more of its traits in the next generation
students should be able to list the following conditions under which NS is made possible: 1) genetic variation of offspring due to sexual reproduction, 2) the environment having a limited supply of resources that cannot possibly sustain all the offspring that are produced by every individual, and 3) differential reproductive success
students should identify NS as the process by which evolution occurs
students should be able to explain why it doesn’t make sense to say “NS acts on populations” but it makes sense to say “NS acts on individuals”
students should be able to explain why it doesn’t make sense to say “an individual has evolved” but it makes sense to say “a population has evolved”
students should be able to explain that mutation, crossing over, and independent assortment are three genetic mechanisms that lead to new gene combinations
students should recognize that new gene combinations amount to different traits found among individuals in a population
students should recognize that new traits may be advantageous or disadvantageous depending on the environment they are found in
students should be able to give an example of an environmental condition and traits that would be advantageous and traits that would be disadvantageous in this condition
students should be able to name a trait that would be advantageous in one environment and disadvantageous in another.
students should be able to define divergence as the accumulation of differences between groups
students should be able to define speciation as the formation of new species
students should be able to recognize that increasing divergence leads to speciation
students should be able to recognize that NS brings about divergence
students should recognize that organisms which are geographically isolated are essentially no longer able to reproduce with one another and therefore create viable offspring.
species become extinct when the environment changes and characteristics of a species are not enough to allow them to survive
most species that have lived on Earth have become extinct (i.e. extinction common)
the fossil record is evidence of extinction and speciation over eons of time.
students should be able to explain how humans can genetically engineer organisms for new traits
Some Big Student Misconceptions:
an individual can evolve we must warn them that only populations can be said to evolve
Natural Selection is goal-directed, for example: bats developed wings because they “wanted” or “needed” them. BUT we must warn them that need does NOT direct change! Otherwise, how would extinction be so common?
changes are induced by the environment and that the mutations which arise depend on the selection pressures present, they may use the following reasoning: “because the environment favored such and such trait, mutants arose in the population that had such and such trait”
Lamarckian notion of inheritance of acquired traits, i.e. the “use and disuse” notion, they may reason like so: “because snakes didn’t use their legs much and they did use their tongues more, over time they lost their legs and their tongues became longer”
*Please note I used already "unpacked" learning goals from here
Prerequisite Knowledge:
Translating Standards into Learning Goals (The “Unpacking”):
Some Big Student Misconceptions:
*Please note I used already "unpacked" learning goals from here